1. Related Technical Fields
Related Technical Fields include navigation systems and methods.
2. Description of the Related Art
In a conventional automobile navigation device, an operator sets a destination by operating an input unit. A route from a current location to a destination is searched based on the destination and the current location of the vehicle detected by a current location detector. The conventional navigation device then guides the operator along the searched route. Conventionally, the optimal route is searched so that the distance from the current location to the destination is shortest, or so that the time required to reach the destination is the shortest.
Conventionally, a system for transmitting road traffic information to the navigation device may be provided. Accordingly, road congestion information may be received and the optimal route can be searched by avoiding congested sections (e.g., see Japanese Unexamined Patent Application Publication No. 8-338736). For example, in one road traffic information communication system called VICS® (Vehicle Information & Communication System), information from traffic control systems is collected. Road traffic information, such as road congestion and traffic restriction, is created and transmitted to the navigation device. The navigation device then searches an optimal route for which the time required to reach the destination is the shortest, based on the road traffic information.
Conventionally, a server of an information center distributes traffic information of a specified area to the navigation device, and the navigation device uses the received traffic information to perform DRG (Dynamic Route Guidance).